vMotion or Cross migration fails when Port Mirroring is active

Products

• VMware vCenter Server
• VMware NSX
• VMware vSphere ESX 8.x

Issue/Introduction

• Virtual machine migrations via vMotion or cross-vCenter cold migration fail during compatibility checks or execution when port mirroring is active.
  
  
• Occurs in environments utilizing vSphere Distributed Switches (vDS) or NSX-T segments where VMs are configured as source or destination pairs.
  
  
• Migration fails with error: "Virtual machine is not ready for the migration operation."
  
  
• Compatibility check reports: "A dvPort connected to the VM is configured to use mirror netstack instance... but the host does not have an active mirror netstack instance."
  
  
• Port mirroring sessions appear blank or invalid in the destination vCenter or NSX Manager after migration.

Environment

ESX: 8.0u3
vCenter: 8.0u3
NSX: 4.2

Cause

Port mirroring sessions are management-plane specific. When a VM moves across vCenter boundaries or to a new vDS, the logical port ID or UUID changes. The destination environment does not automatically inherit the session mapping from the source.

Resolution

1. Document the current mirroring session configuration (Source, Destination, Direction, and Type).
   
   
2. Perform the migration of the VM pairs.
   
   
3. For vDS-backed Port Mirroring:
   Navigate to the Target vDS > Configure > Port Mirroring.
   Create a new session selecting the new port IDs of the migrated VMs.
   
   
4. For NSX-backed Port Mirroring:
   Log in to the NSX Manager UI.
   Navigate to Plan & Troubleshoot > Traffic Analysis > Port Mirroring.
   Create a new session using the new Logical Port UUIDs assigned to the VMs post-migration.
   
   
5. Verify that "Normal I/O on destination ports" is set to Allowed if management connectivity is required for the sniffer VM.

Additional Information

Port Mirroring Interoperability